KR20200048790A - Pressure sensitive adhesive composition - Google Patents

Abstract

The present invention relates to an adhesive composition and to an optical laminate comprising the same. The optical laminate secures stable durability even at high temperature, especially at ultra high temperatures of about 100°C, suppresses or prevents foaming phenomenon in an adhesive layer, and is excellent in physical properties required for other optical laminates. In addition, even when the adhesive is disposed adjacent to an electrode, the corrosion of the electrode is suppressed.

Description

Adhesive composition {PRESSURE SENSITIVE ADHESIVE COMPOSITION}

The present application relates to an adhesive composition, an optical laminate comprising an adhesive layer formed therefrom.

Various optical films such as polarizers are applied to various display devices such as a liquid crystal display (LCD) or an organic light emitting diode (OLED). Such an optical film is generally attached to a display device with an adhesive. In this case, high reliability is required for the optical film and the adhesive. For example, it is required that the optical film or adhesive used in a navigation or vehicle display is stably maintained even when maintained at a very high temperature for a long time.

A typical polarizing plate, which is an optical film, is a multi-layered structure including a polarizer that is a device that generally exhibits a polarization function and a protective film that protects the polarizer. As a protective film of the polarizer, a so-called TAC (triacetyl cellulose) -based film is used. However, since the TAC film has high moisture permeability, defects such as light leakage and warpage occur as moisture penetrates the polarizer under high temperature and high humidity conditions. Due to this moisture permeation problem, a method of replacing the TAC film with a low moisture permeable film is considered, but in the case of a low moisture permeable film having hydrophobicity, there is a problem of low adhesion between the pressure-sensitive adhesive and the substrate, that is, low keying force. have.

On the other hand, in the case of a polarizing plate used in a vehicle display, an adhesive containing an acid monomer is used to secure cohesive force through reaction with a crosslinking agent and the like and provide proper high temperature reliability to the polarizing plate. Specifically, the acid-based monomer increases the hardness of the pressure-sensitive adhesive resin itself, and increases the adhesion due to the polarity of the acid-based monomer. However, the acid component may, for example, corrode ITO of the LCD panel, causing stains or poor touch.

One object of the present application is to provide an adhesive composition and an optical laminate.

The above and other other objects of the present application can be solved by the present application described in detail below.

In an example related to the present application, the present application relates to an adhesive composition. The adhesive composition can be used to form an adhesive layer of an optical laminate including a polarizer. The pressure-sensitive adhesive composition and the pressure-sensitive adhesive layer provided according to the present application may solve the following problems in the prior art.

Specifically, when the low moisture-permeable film forms an optical laminate together with the pressure-sensitive adhesive layer, foaming phenomenon is likely to occur in the pressure-sensitive adhesive due to the low moisture permeability and hydrophobicity of the low moisture-permeable film, and particularly, the foaming phenomenon is more easily performed under the conditions of 100 ° C or higher. There is a provoking problem. That is, even when a low moisture-permeable optical film is applied, a foaming phenomenon is suppressed, and a pressure-sensitive adhesive capable of providing stable durability is required.

As another problem, the acrylic film has relatively poor adhesiveness, and thus the adhesion of the substrate between the polarizing plate having the low moisture permeability acrylic film and the adhesive, that is, the keying force is not good. Particularly, in a high temperature condition, separation between the polarizing plate and the adhesive may occur, and when the polarizing plate is separated from the adhesive, a problem arises in that the adhesive sticks off the polarizing plate and remains on the adhesive.

In view of this, the pressure-sensitive adhesive composition of the present application is configured to improve adhesion, high temperature durability, and keying force. More specifically, when the inventor of the present application uses a pressure-sensitive adhesive composition containing a cross-linking agent of a specific structure and a different cross-linking agent in a predetermined content range, the pressure-sensitive adhesive layer formed therefrom may be modified in an adjacent configuration (for example, a low moisture-permeable film or polarizer). It can be sensitively reacted, and as a result, it was confirmed that the foaming phenomenon can be suppressed or prevented while stably maintaining high temperature durability even when a low moisture-permeable optical film is applied to the optical laminate.

The adhesive composition includes an adhesive polymer and at least two isocyanate compounds. Accordingly, the polymer may be included in the pressure-sensitive adhesive layer described below in a state crosslinked by a crosslinking agent such as an isocyanate compound. To this end, as described later, the adhesive polymer may include a crosslinkable or polar functional group-containing monomer unit.

In the present application, the pressure-sensitive adhesive composition simultaneously comprises an aromatic isocyanate compound (B) and a non-aromatic isocyanate compound (C) as a crosslinking agent. The compound (C) is a compound derived from HDI (hexamethylene diisocyanate), and may have a structure described below. Specifically, the inventors of the present application confirmed that, in addition to an aromatic isocyanate compound such as TDI (toluene diisocyanate), a slower curing rate compound (C) can be applied as a crosslinking agent to improve anchoring power. Since the curing speed of the compound (C) is slow, the time during which the cohesive force of the pressure-sensitive adhesive itself is formed may be slow, but the compound (C) can be used to improve the adhesion of the substrate by the slow curing speed, and as a result, the anchoring power of the pressure-sensitive adhesive layer is improved It works. However, when only the compound (C) is used, there is a risk that the cohesive force of the pressure-sensitive adhesive itself is too low, so it is preferable to use the compound (B) and the compound (C) in appropriate amounts.

Specifically, the pressure-sensitive adhesive composition may include an aromatic isocyanate (B) as an isocyanate compound. The kind of aromatic isocyanate compound is not particularly limited. For example, toluene diisocyanate (TDI), xylylenediisocyanate (XDI), bis (isocyanatoethyl) benzene, bis (isocyanatopropyl) benzene, bis (isocyanatobutyl) benzene, bis (Isocyanatomethyl) naphthalene, bis (isocyanatomethyl) diphenyl ether, phenylenediisocyanate, ethylphenylenediisocyanate, isopropylphenylenediisocyanate, dimethylphenylenediisocyanate, diethylphenylenediisocyanate, diisopropyl Phenylenediisocyanate, trimethylbenzenetriisocyanate, benzenetriisocyanate, biphenyldiisocyanate, toluidinediisocyanate, diphenylmethanediisocyanate (MDI), 3,3-dimethyldiphenylmethane-4,4-diisocyanate, bibenzyl- 4,4-diisocyanate, bis (isocyanatophenyl) ethylene, 3,3-dimethoxybiphenyl-4,4-diisocyanae , Hexahydro-benzene diisocyanate, hexahydro-di-aromatic isocyanate compounds such as diphenylmethane-4,4-diisocyanate can be used.

In addition, the pressure-sensitive adhesive composition includes an isocyanate compound (C) represented by the following formula (1).

[Formula 1]

In Chemical Formula 1, R is a straight or branched alkyl or alkylene group having 1 to 10 carbon atoms, A1, A2 and A3 are each independently an alkylene group or an alkylidene group, and m is an integer between 2 and 5 , n is an integer between 2 and 10

In one example, R in Formula 1 may be an alkyl group having 1 to 4 carbon atoms, and may be, for example, a methyl, ethyl, propyl or butyl group unsubstituted or substituted according to the number of n.

In one example, in Formula 1, A1, A2, and A3 may each independently be alkylene having 1 to 8 carbon atoms, for example, methylene, ethylene, pentylene, hexylene, or octylene.

In one example, such a compound may be obtained, for example, by reacting a polyester-based polyol, an isocyanate, and a polyfunctional alcohol having two or more alcohol functional groups. The functional group of the polyfunctional alcohol undergoes a dehydration condensation reaction with polyester, and forms a three-dimensional structure. Preferably, there may be three or more reactors of the polyfunctional alcohol, and non-limiting examples of such polyfunctional alcohols include trimethylolpropane, trimethylolmethane, glycerin or pentaerythritol.

Since such a compound has a relatively slow crosslinking rate, more crosslinking agents can be used to improve adhesion to the substrate, and it can have elasticity (flexible properties) due to the unique structure described above, resulting in improved anchoring power It is believed to contribute.

In one example, the pressure-sensitive adhesive composition may include the isocyanate compound (C) represented by Chemical Formula 1 based on 100 parts by weight of the aromatic isocyanate (B) in a range of 5 to 60 parts by weight. More specifically, the lower limit of the content of the isocyanate compound (C) is, for example, 6 parts by weight or more, 7 parts by weight or more, 8 parts by weight or more, 9 parts by weight or more, 10 parts by weight or more, 11 parts by weight or more, 12 It may be at least 13 parts by weight, at least 13 parts by weight, at least 14 parts by weight, or at least 15 parts by weight. And, the upper limit may be, for example, 55 parts by weight or less, 50 parts by weight or less, 45 parts by weight or less, or 40 parts by weight or less, more specifically 35 parts by weight or less, 34 parts by weight or less, 33 parts by weight or less , 32 parts by weight or less, 31 parts by weight or less, 30 parts by weight or less, 29 parts by weight or less, 28 parts by weight or less, 27 parts by weight or less, 26 parts by weight or less, or 25 parts by weight or less. When satisfying the above content range, it is possible to secure the anchoring power and durability of the desired adhesive.

In one example, the pressure-sensitive adhesive composition may further include a crosslinking agent (D) other than isocyanate. The type of such crosslinking agent is not particularly limited, and a known crosslinking agent can be used. For example, an epoxy-based crosslinking agent, an aziridine-based crosslinking agent, a metal chelate-based crosslinking agent, and the like can be used. Specifically, as the epoxy-based crosslinking agent, ethylene glycol diglycidyl ether, triglycidyl ether, trimethylolpropane triglycidyl ether, N, N, N ', N'-tetraglycidyl ethylenediamine and glycerin diglycine One or more selected from the group consisting of cydyl ether may be used, and as the aziridine-based crosslinking agent, N, N-toluene-2,4-bis (1-aziridinecarboxamide), N, N'-diphenylmethane Group consisting of -4,4'-bis (1-aziridinecarboxamide), triethylene melamine, bisisophthaloyl-1- (2-methylaziridine) and tri-1-aziridinylphosphine oxide One or more selected from may be used, and as the metal chelating crosslinking agent, a polyvalent metal such as aluminum, iron, zinc, tin, titanium, antimony, magnesium, and / or vanadium coordinates acetyl acetone or ethyl acetoacetate. Can be used, but the above But it is not limited to those.

In one example, the pressure-sensitive adhesive composition may include the crosslinking agent (D) in the range of 0.1 to 5 parts by weight based on 100 parts by weight of the aromatic isocyanate (B). More specifically, the lower limit of the content of the crosslinking agent (D) may be, for example, 0.2 parts by weight or more, 0.3 parts by weight or more, 0.4 parts by weight or more, or 0.5 parts by weight or more. And the upper limit may be, for example, 4 parts by weight or less, 3 parts by weight or less, or 2 parts by weight or less.

In one example, with respect to the content of the total crosslinking agent used, the pressure-sensitive adhesive composition may include a crosslinking agent in the range of 0.001 parts by weight to 10 parts by weight relative to 100 parts by weight of the adhesive polymer (A). For example, the pressure-sensitive adhesive composition may include cross-linking agents (B and C) in the range of 0.001 parts by weight to 10 parts by weight relative to 100 parts by weight of the adhesive polymer (A). Or, for example, the pressure-sensitive adhesive composition may include a crosslinking agent (B, C, and D) in the range of 0.001 parts by weight to 10 parts by weight relative to 100 parts by weight of the adhesive polymer (A). When the above range is satisfied, it is possible to prevent a decrease in durability reliability, such as interlayer peeling or lifting, while maintaining the cohesive force of the pressure sensitive adhesive.

The content ratio of the total crosslinking agent may be about 0.005 parts by weight or more, 0.01 parts by weight or more, 0.05 parts by weight or more, or 0.1 parts by weight or more, and about 9 parts by weight or less, 8 parts by weight or less, 7 parts by weight or less, 6 It may be up to 5 parts by weight, up to 4 parts by weight, up to 3 parts by weight, up to 2 parts by weight, or up to 1.5 parts by weight.

In one example, the adhesive polymer may be an acrylic polymer. The term acrylic polymer has a property capable of forming an adhesive, and may mean a polymer containing an acrylic monomer unit as a main component. The term acrylic monomer may mean a derivative of acrylic acid or methacrylic acid, such as acrylic acid, methacrylic acid or (meth) acrylic acid ester. In addition, being included as the main component in the above, the proportion of the component is 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 75% or more in the polymer (A) by weight, It may mean a case of 80% or more, 85% or more, 90% or more, or 95% or more. At this time, the (weight) ratio of the component may be used in the same sense as the content of the monomer used in forming the polymer. The upper limit of the ratio may be 100%. In addition, the unit contained in the polymer means a state in which the monomer forms a main chain and / or a side chain of the polymer through a polymerization reaction.

In one example, the adhesive polymer is (1) an alkyl (meth) acrylate unit having an alkyl group having 4 or more carbon atoms, (2) an alkyl (meth) acrylate unit having an alkyl group having 3 or less carbon atoms, (3) aromatic Group-containing monomer units and (4) polar functional group-containing monomer units. Such a monomer composition can ensure that the pressure-sensitive adhesive layer exhibits excellent high-temperature durability, and at the same time maintains excellent reworkability, cutability, lifting and anti-foaming properties, which are required for other pressure-sensitive adhesives.

In the above (1) unit, in consideration of the cohesive force, glass transition temperature or tackiness of the pressure-sensitive adhesive, a unit having an alkyl group having 4 or more carbon atoms, for example, an alkyl (meth) acrylate having an alkyl group having 4 to 14 carbon atoms, Can be used. Examples of the above alkyl (meth) acrylate include n-butyl (meth) acrylate, t-butyl (meth) acrylate, sec-butyl (meth) acrylate, pentyl (meth) acrylate, and 2-ethylhexyl (Meth) acrylate, 2-ethylbutyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate and tetra Decyl (meth) acrylate, and the like, and one or two or more of the above may be applied. Generally, n-butyl acrylate or 2-ethylhexyl acrylate is used.

The ratio in the polymer of the unit (1) is not particularly limited, but may be in the range of about 50 to 70% by weight. The ratio may be up to about 85% by weight in other examples.

As the unit (2), an alkyl (meth) acrylate unit having an alkyl group having 3 or less carbon atoms is used. These units can ensure that the pressure-sensitive adhesive secures excellent durability and reliability at high temperatures. As the monomer capable of forming the unit, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate or isopropyl (meth) acrylate, etc. may be exemplified, and suitable examples Is methyl acrylate.

The unit (2) may be included in the polymer in a ratio of about 15 to 45 parts by weight based on 100 parts by weight of the unit (1). Specifically, the lower limit of the ratio is, for example, 16 parts by weight or more, 17 parts by weight or more, 18 parts by weight or more, 19 parts by weight or more, 20 parts by weight or more, 21 parts by weight or more, 22 parts by weight or more, 23 parts by weight It may be at least 24 parts by weight, at least 25 parts by weight, at least 26 parts by weight, at least 27 parts by weight, at least 28 parts by weight, at least 29 parts by weight, or at least 30 parts by weight. And the upper limit of the ratio is, for example, 40 parts by weight or less, 39 parts by weight or less, 38 parts by weight or less, 37 parts by weight or less, 36 parts by weight or less, 35 parts by weight or less, 34 parts by weight or less, 33 parts by weight or less , 32 parts by weight or less, 31 parts by weight or less, or 30 parts by weight or less.

As the unit (3), a unit of an aromatic group-containing monomer, for example, a unit of an (meth) acrylate-based monomer having an aromatic ring is used.

The type of the aromatic group-containing monomer capable of forming such a unit is not particularly limited, and for example, a monomer represented by the following Chemical Formula 2 may be exemplified.

[Formula 2]

In Formula 2, R1 represents hydrogen or alkyl, A represents alkylene, n represents an integer in the range of 0 to 3, Q represents a single bond, -O-, -S- or alkylene, P represents Aromatic ring.

In Formula 2, a single bond means a case in which the atomic groups on both sides are directly bonded without mediating a separate atom.

In Formula 2, R1 may be, for example, hydrogen or alkyl having 1 to 4 carbon atoms, or hydrogen, methyl or ethyl.

In the definition of Formula 2, A may be alkylene having 1 to 12 or 1 to 8 carbons, for example, methylene, ethylene, hexylene or octylene.

In Formula 2, n may be, for example, a number in the range of 0 to 2, or 0 or 1.

Q in Formula 2 may be a single bond, -O- or -S-.

In Formula 2, P is a substituent derived from an aromatic compound, and may be, for example, a functional group derived from an aromatic ring having 6 to 20 carbon atoms, for example, phenyl, biphenyl, naphthyl or anthracenyl.

In Formula 2, the aromatic ring may be optionally substituted by one or more substituents, and specific examples of the substituents are halogen or alkyl, halogen or alkyl having 1 to 12 carbons, chlorine, bromine, methyl, ethyl, and propyl. , Butyl, nonyl or dodecyl, but is not limited thereto.

Specific examples of the compound of Formula 2 are phenoxy ethyl (meth) acrylate, benzyl (meth) acrylate, 2-phenylthio-1-ethyl (meth) acrylate, 6- (4,6-dibromo-2 -Isopropyl phenoxy) -1-hexyl (meth) acrylate, 6- (4,6-dibromo-2-sec-butyl phenoxy) -1-hexyl (meth) acrylate, 2,6-di Bromo-4-nonylphenyl (meth) acrylate, 2,6-dibromo-4-dodecyl phenyl (meth) acrylate, 2- (1-naphthyloxy) -1-ethyl (meth) acrylate , 2- (2-naphthyloxy) -1-ethyl (meth) acrylate, 6- (1-naphthyloxy) -1-hexyl (meth) acrylate, 6- (2-naphthyloxy) -1 -Hexyl (meth) acrylate, 8- (1-naphthyloxy) -1-octyl (meth) acrylate and 8- (2-naphthyloxy) -1-octyl (meth) acrylate Mixing may be mentioned, but is not limited thereto.

The (3) unit may be included in the polymer in a ratio of about 10 to 40 parts by weight relative to 100 parts by weight of the (1) unit. Specifically, the lower limit of the ratio is, for example, 11 parts by weight or more, 12 parts by weight or more, 13 parts by weight or more, 14 parts by weight or more, 15 parts by weight or more, 16 parts by weight or more, 17 parts by weight or more, 18 parts by weight or more Or more, 19 parts by weight or more, or 20 parts by weight or more. And, the upper limit of the ratio is, for example, 35 parts by weight or less, 34 parts by weight or less, 33 parts by weight or less, 32 parts by weight or less, 31 parts by weight or less, 30 parts by weight or less, 29 parts by weight or less, 28 parts by weight or less , 27 parts by weight or less, 26 parts by weight or less, or 25 parts by weight or less.

As the unit (4), a unit of a monomer having a hydroxy group or a carboxyl group as a polar functional group may be used. If necessary, these units may serve to impart cohesive force or the like through reaction with a crosslinking agent or the like described below. In order to ensure proper high-temperature reliability and the like, as the monomer having the polar functional group, a hydroxyalkyl (meth) acrylate or a carboxyl group-containing monomer having a hydroxyalkyl group having 3 to 6 carbon atoms can be used.

As a hydroxyalkyl (meth) acrylate having a hydroxyalkyl group having 3 to 6 carbon atoms, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate or 6-hydroxy Hexyl (meth) acrylate and the like can be exemplified, and 4-hydroxybutyl (meth) acrylate can be used in one example.

Examples of the carboxyl group-containing monomer include (meth) acrylic acid, 2- (meth) acryloyloxy acetic acid, 3- (meth) acryloyloxy propyl acid, 4- (meth) acryloyloxy butyric acid, and acrylic acid doublets , Itaconic acid, maleic acid, maleic anhydride, and the like can be exemplified, and acrylic acid can generally be applied.

However, when the pressure-sensitive adhesive layer is used adjacent to an electrode such as ITO (Indium Tin Oxide), if the pressure-sensitive adhesive layer contains a large amount of carboxyl groups, corrosion of the electrode may be caused, which may adversely affect the performance of the device. Therefore, the component having a carboxyl group is not applied, or the upper limit of the application rate needs to be limited.

The (4) unit may be included in the polymer in a ratio of about 0.5 to 5 parts by weight relative to 100 parts by weight of the (1) unit. In another example, the ratio may be about 1.0 part by weight or more or 1.5 parts by weight or more, or about 5 parts by weight or less, 4.5 parts by weight or 4.0 parts by weight or less. Particularly, when the (4) unit is a carboxyl group-containing monomer unit, the ratio is about 4.5 parts by weight or less, about 4 parts by weight or less, about 3.5 parts by weight or less, and about 3 parts by weight based on 100 parts by weight of the (1) unit. Parts or less, about 2.5 parts by weight or less, or 2 parts by weight or less.

The adhesive polymer contains the units of the above-mentioned monomers, and if necessary, the ratio is adjusted to ensure stable durability at a high temperature in the pressure-sensitive adhesive layer, and the physical properties required for other pressure-sensitive adhesive layers are also stably maintained, adjacent to the electrode. Even if disposed, it may not cause corrosion or the like of the corresponding electrode.

If necessary, the adhesive polymer may further include other known units in addition to the above-mentioned units.

The adhesive polymer can be produced by a known polymerization method using the above-mentioned monomers.

The pressure-sensitive adhesive composition may further include other known and necessary additives in addition to the aforementioned components. Examples of such additives include coupling agents such as silane coupling agents, antistatic agents, tackifiers, and ultraviolet stabilizers; Antioxidants; Colorant; Adjuvant; Fillers; Antifoaming agent; Surfactants; Photopolymerizable compounds such as polyfunctional acrylates; And one or more selected from the group consisting of plasticizers, but is not limited thereto.

In another example related to the present application, the present application relates to an optical laminate. The optical laminate includes an optical element and a pressure-sensitive adhesive layer formed on one or both surfaces of the optical element. If necessary, a release film may be attached to the pressure-sensitive adhesive layer formed on one or both surfaces of the optical element.

The types of optical elements included in the optical laminate are not particularly limited, and may be various types of elements used in display devices. For example, the optical element may be a polarizing plate, a polarizer, a polarizer protective film, a retardation film, a viewing angle compensation film, or a brightness enhancing film. In this specification, the terms polarizer and polarizer refer to objects that are distinguished from each other. The polarizer refers to a film, sheet or device itself that exhibits a polarization function, and the polarizer refers to an optical device including other elements together with the polarizer. Other elements that may be included in the optical element together with the polarizer may include, but are not limited to, a polarizer protective film or a retardation layer.

The optical element of the present application may include at least a so-called low moisture-permeable optical film. In the present application, the term low moisture permeability optical film is an optical film having low moisture permeability, for example, water vapor transmissiion rate (WVTR) measured for 24 hours at a temperature of 37 ° C. and a relative humidity of 88.5 ± 0.5%. It means an optical film of about 100 g / m ² · day or less. In one example, the moisture permeability is about 95 g / m ² · day or less, 90 g / m ² · day or less, 85 g / m ² · day or less, 80 g / m ² · day or less, 75 g / m ² · day Or less, 70 g / m ² · day or less, 65 g / m ² · day or less, 60 g / m ² · day or less, 55 g / m ² · day or less, 50 g / m ² · day or less, 45 g / m ² · day or less, 40 g / m ² · day or less, 35 g / m ² · day or less, 30 g / m ² · day or less, 25 g / m ² · day or less, 20 g / m ² · day or less , 15 g / m ² · day or less, 10 g / m ² · day or less, 8 g / m ² · day or less, or 6 g / m ² · day or less. The lower limit of the moisture permeability is not particularly limited, but is about 0.01 g / m ² · day or more, 0.1 g / m ² · day or more, 0.5 g / m ² · day or more, 1 g / m ² · day or more, 1.5 g / m ² · day or more, 2 g / m ² · day or more, 2.5 g / m ² · day or more, 3 g / m ² · day or more, 3.5 g / m ² · day or more, 4 g / m ² · day Or more than 4.5 g / m ² · day. The thickness of the optical film having the moisture permeability is not particularly limited. That is, an optical film having a thickness generally applied as an optical film and exhibiting the moisture permeability at the thickness can be applied to the optical device of the present application. In one example, the thickness of the optical film may be in a range of about 10 to 100 μm. The moisture permeability can be measured according to a method known in the art. As representative standards for measuring moisture permeability, ASTM F1249 or ISO15506-3 is known, and the moisture permeability of the present application can be measured according to an appropriate method.

Various types of the optical film having low moisture permeability are known, and examples thereof include a cycloolefin polymer (COP) film or an acrylic film, or a polyester film such as a PET (poly (ethylene terephthalate)) film. Can be. These films have a lower degree of hydrophilicity, that is, hydrophobic films, than TAC films, which are commonly used as protective films.

The low moisture-permeable films as described above may be used as protective films of polarizers or materials such as retardation films.

In one example, the low moisture-permeable film used in the device of the present application may be an acrylic film. In the case of a commercially available TAC film, the moisture permeability (WVTR) measured as described above is about 100 g / m ² · day or more, and the moisture permeability of the acrylic film is about 5 to 35 g / m ² · day. As described above, the acrylic film has a poor drawing ability than other films, but in the present application using the adhesive having the above-described configuration, even when an acrylic film is used, the durability and the drawing ability of the optical laminate can be improved.

When such a low moisture-permeable film forms an optical laminate together with the pressure-sensitive adhesive layer, foaming phenomenon is likely to occur in the pressure-sensitive adhesive due to the low moisture permeability and hydrophobicity of the film, and particularly, the foaming phenomenon is more easily performed under a high temperature condition of 100 ° C. or higher. Is triggered. Considering this, it is necessary to improve the adhesion between the pressure-sensitive adhesive and the substrate, that is, the keying force.

The pressure-sensitive adhesive of the above configuration according to the present application can suppress the foaming phenomenon while stably maintaining the durability even when the low moisture-permeable optical film is applied. Specifically, since the pressure-sensitive adhesive is formed from a cross-linking agent-containing composition containing a specific amount of a cross-linking agent of a specific structure, it can react sensitively to deformation of adjacent components (eg, a low moisture-permeable film or polarizer). Therefore, when compared with the conventional adhesive optical laminate comprising a low moisture-permeable film, lifting, peeling or foaming between adjacent layer structures is suppressed, and as a result, light leakage preventing properties of the polarizing plate can be further improved.

A polarizing plate is a typical example of the optical element including the low moisture-permeable film. Such a polarizing plate may include the low moisture-permeable optical film together with a polarizer exhibiting a polarization function, and the low moisture-permeable optical film may be included in the polarizing plate as a protective film or a retardation film for the polarizer. Therefore, in one example according to the present application, the polarizing plate may include a polarizer and the low moisture-permeable optical film formed on one surface of the polarizer.

In the structure of the polarizing plate, the low moisture-permeable optical film may be formed on only one surface of the polarizer, or the low moisture-permeable optical film may be formed on both surfaces thereof. When formed on only one surface, there may be no optical film on the other surface, another optical functional layer may exist, or an optical film having high moisture permeability may be present. When the low moisture-permeable optical film is formed on only one surface of the polarizer, the low moisture-permeable optical film, which will be described later, may be positioned closer to the pressure-sensitive adhesive layer, which will be described later, compared to the polarizer. For example, the optical laminated body may sequentially include a polarizer, a low moisture-permeable film, and an adhesive layer.

The polarizer that can be included in the optical laminate of the present application is basically not particularly limited. For example, a polyvinyl alcohol polarizer can be used as a polarizer. The term polyvinyl alcohol polarizer may mean, for example, a polyvinyl alcohol (hereinafter, referred to as PVA) -based resin film containing an anisotropic absorbent material such as iodine or a dichroic dye. Such a film can be produced by including an anisotropic absorbent material in a polyvinyl alcohol-based resin film and oriented by stretching or the like. Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol, polyvinyl formal, polyvinyl acetal, or saponified products of ethylene-vinyl acetate copolymers. The polymerization degree of the polyvinyl alcohol-based resin may be about 100 to 5,000 or 1,400 to 4,000, but is not limited thereto.

Such a polyvinyl alcohol polarizer can be produced, for example, by performing at least a dyeing process, a crosslinking process, and a stretching process on a PVA-based film. In the dyeing step, the crosslinking step and the stretching step, each treatment bath of a dyeing bath, a crosslinking bath, and a stretching bath is used, and the treatment liquid according to each step can be used for each treatment bath.

In the dyeing process, the anisotropic absorbent material may be adsorbed and / or oriented on the PVA-based film. This dyeing process can be carried out in conjunction with the stretching process. Dyeing may be performed by immersing the film in a solution containing an anisotropic absorbent material, for example, an iodine solution. As the iodine solution, for example, an aqueous solution containing iodine ions by an iodide compound which is an iodine and a dissolution aid may be used. As the iodide compound, for example, potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide or titanium iodide may be used. The concentration of iodine and / or iodide ions in the iodine solution can be adjusted in consideration of the optical properties of the desired polarizer, and such a control method is known. In the dyeing process, the temperature of the iodine solution is usually 20 ° C to 50 ° C, about 25 ° C to 40 ° C, and the immersion time is usually about 10 seconds to 300 seconds or 20 seconds to 240 seconds, but is not limited thereto.

The crosslinking process performed in the manufacturing process of the polarizer may be performed, for example, using a crosslinking agent such as a boron compound. The order of the crosslinking process is not particularly limited, and may be performed, for example, with a dyeing and / or stretching process, or separately. The crosslinking process may be carried out multiple times. As the boron compound, boric acid or borax may be used. The boron compound may be generally used in the form of an aqueous solution or a mixed solution of water and an organic solvent, and an aqueous boric acid solution is usually used. The concentration of boric acid in the aqueous boric acid solution may be selected in an appropriate range in consideration of crosslinking degree and heat resistance. An iodide compound such as potassium iodide can also be contained in an aqueous boric acid solution or the like.

The crosslinking process can be performed by immersing the PVA-based film in a boric acid aqueous solution or the like. In this process, the treatment temperature is usually in the range of 25 ° C or higher, 30 ° C to 85 ° C, or 30 ° C to 60 ° C, and the treatment time is usually 5 seconds to 800 seconds or 8 seconds to 500 seconds.

The stretching step is generally performed by uniaxial stretching. Such stretching may be performed together with the dyeing and / or crosslinking process. The stretching method is not particularly limited, and for example, a wet stretching method may be applied. In this wet stretching method, for example, it is common to perform stretching after dyeing, but stretching may be performed with crosslinking, or may be performed multiple times or in multiple stages.

An iodide compound such as potassium iodide may be contained in the treatment liquid applied to the wet stretching method, and the light blocking rate may also be controlled by adjusting the ratio in this process. In the stretching, the treatment temperature is usually in the range of 25 ° C or higher, 30 ° C to 85 ° C, or 50 ° C to 70 ° C, and the treatment time is usually 10 seconds to 800 seconds or 30 seconds to 500 seconds, but is not limited thereto. .

In the stretching process, the total draw ratio may be adjusted in consideration of orientation characteristics, etc., and the total draw ratio may be 3 to 10 times, 4 to 8 times, or 5 to 7 times based on the original length of the PVA-based film. , But is not limited thereto. In the above, the total stretching magnification may mean a cumulative stretching magnification including stretching in each step when stretching is performed also in a swelling process other than the stretching process. The total draw ratio may be adjusted to an appropriate range in consideration of orientation, the processability of a polarizer, or the possibility of stretch cutting.

In the manufacturing process of the polarizer, in addition to the dyeing, crosslinking and stretching, a swelling process may be performed before the process. It is possible to clean the surface of the PVA-based film or the anti-blocking agent by swelling, and there is also an effect of reducing unevenness such as dyeing variation.

In the swelling process, water, distilled water, or pure water may be used. The main component of the treatment liquid is water, and if necessary, additives such as an iodide compound such as potassium iodide or a surfactant, alcohol, etc. may be included in a small amount. In this process, it may be possible to control the aforementioned light blocking rate through adjustment of process parameters.

The treatment temperature in the swelling process is usually 20 ° C to 45 ° C or 20 ° C to 40 ° C, but is not limited thereto. Since the swelling deviation can cause dyeing deviation, the process parameters can be adjusted so that the occurrence of such swelling deviation is suppressed as much as possible.

If necessary, proper stretching can also be performed in the swelling process. The stretching ratio may be 6.5 times or less, 1.2 to 6.5 times, 2 to 4 times, or 2 to 3 times, based on the original length of the PVA-based film. The stretching in the swelling process can control the stretching in the stretching step performed after the swelling process to a small extent, and control the stretching of the film so as not to occur.

In the manufacturing process of the polarizer, metal ion treatment may be performed. Such treatment is performed, for example, by immersing the PVA-based film in an aqueous solution containing a metal salt. This allows metal ions to be contained within the tube. In this process, the color tone of the PVA-based polarizer can be adjusted by adjusting the type or ratio of metal ions. As the metal ions that can be applied, metal ions of transition metals such as cobalt, nickel, zinc, chromium, aluminum, copper, manganese, or iron can be exemplified, and color tone can be controlled by selecting an appropriate type. have.

In the manufacturing process of the polarizer, a washing process may be performed after dyeing, crosslinking, and stretching. Such a washing process can be performed with a solution of an iodine compound such as potassium iodide. In this process, the above-described light blocking rate may be controlled through the concentration of the iodide compound in the solution or the treatment time of the cleaning process. Therefore, the concentration of the iodide compound and the treatment time with the solution can be adjusted in consideration of the light blocking rate. However, the washing process may be performed using water.

The washing with water and washing with an iodine compound solution may be combined, and a solution containing liquid alcohol such as methanol, ethanol, isopropyl alcohol, butanol or propanol may also be used.

After this process, a drying process may be performed to prepare a polarizer. In the drying process, for example, in consideration of the moisture content required for the polarizer, etc., it may be performed at an appropriate temperature for an appropriate time, and these conditions are not particularly limited.

In one example, in order to secure the durability of the optical laminate, in particular, high temperature reliability, a polyvinyl alcohol polarizer including a potassium component such as potassium ion and a zinc component such as zinc ion may be used as the polarizer. When a polarizer containing such a component is used, it is possible to provide an optical laminate stably maintaining durability even under high temperature conditions, particularly under extremely high temperature conditions of 100 ° C or higher.

The proportion of the potassium and zinc components can be further adjusted. For example, the ratio (K / Zn) of the potassium component (K) and the zinc component (Zn) contained in the polyvinyl alcohol polarizer may be in the range of 0.2 to 6 in one example. The ratio (K / Zn) may be about 0.4 or more, 0.6 or more, 0.8 or more, 1 or more, 1.5 or more, 2 or more, or 2.5 or more, and 5.5 or less, about 5 or less, about 4.5 or less, or about 4 or less in other examples. have.

In addition, the proportion of the potassium component contained in the polyvinyl alcohol polarizer may be about 0.1 to 2% by weight. The proportion of the potassium component may be at least about 0.15% by weight, at least about 0.2% by weight, at least about 0.25% by weight, at least about 0.3% by weight, at least about 0.35% by weight, at least 0.4% by weight, or at least about 0.45% by weight in other examples. And about 1.95 wt% or less, about 1.9 wt% or less, about 1.85 wt% or less, about 1.8 wt% or less, about 1.75 wt% or less, about 1.7 wt% or less, about 1.65 wt% or less, about 1.6 wt% or less, Up to about 1.55 wt%, up to about 1.5 wt%, up to about 1.45 wt%, up to about 1.4 wt%, up to about 1.35 wt%, up to about 1.3 wt%, up to about 1.25 wt%, up to about 1.2 wt%, up to about 1.15 It may be less than or equal to about 1.1% by weight, less than or equal to about 1.05% by weight, less than or equal to about 1% by weight, less than or equal to about 0.95%, less than or equal to about 0.95%, or less than or equal to about 0.85% by weight.

In one example, the ratio of the potassium component and the zinc component may be included to satisfy Equation A below.

[Formula A]

0.70 to 0.95 = 1 / (1 + Q × d / R)

In Formula A, Q is the ratio (K / Zn) of the molar mass of potassium components (K, 39.098 g / mol) and the molar mass of zinc components (Zn, 65.39 g / mol) contained in the polyvinyl alcohol polarizer, d Is the thickness before stretching of the polyvinyl alcohol polarizer (㎛) / 60㎛, R is the weight ratio of the potassium component contained in the polyvinyl alcohol polarizer (K, unit: weight%) and the weight ratio of the zinc component (Zn, unit: weight %) Ratio (K / Zn).

By including potassium and zinc components in the polarizer in the form described above, it may be possible to provide a polarizer having excellent reliability at high temperatures.

The thickness of the polarizer as described above is not particularly limited, and may be formed to an appropriate thickness according to the purpose. Typically, the thickness of the polarizer may be in the range of 5 μm to 80 μm, but is not limited thereto.

The optical laminate may include an adhesive layer formed on one or both surfaces of the optical element. The pressure-sensitive adhesive layer contains an adhesive polymer. The pressure-sensitive adhesive layer may contain the pressure-sensitive adhesive polymer as a main component. In other words, the ratio of the adhesive polymer to the total weight of the pressure-sensitive adhesive layer is 55% by weight, 60% by weight, 65% by weight, 70% by weight, 75% by weight, 80% by weight, 85% by weight or more Or it may be 90% by weight or more. The upper limit of the ratio is not particularly limited, and may be, for example, 100% by weight or less, about 98% by weight or less, or 95% by weight or less. As described above, the adhesive polymer may be included in the adhesive layer in a state crosslinked by a crosslinking agent.

The properties of the pressure-sensitive adhesive layer can be controlled in order to secure excellent durability under high temperature conditions, particularly at 100 ° C or higher, and to suppress or prevent foaming and the like even when applied with an optical film having low moisture permeability.

The present application also relates to a display device comprising the optical laminate as described above. The device may include, for example, a display panel in which the optical laminate is attached via the above-mentioned pressure-sensitive adhesive layer. In the above, the type of the display panel is not particularly limited, and may be, for example, a known LCD panel or OLED panel. In addition, the position at which the optical laminate is attached to the panel, etc., can also be performed according to a known method.

According to the present application, it is possible to provide an optical laminate in which foaming is suppressed because it provides stable durability even at a high temperature, particularly at an extremely high temperature of about 100 ° C. or higher, and has excellent drawing ability. Further, according to the present application, even when disposed adjacent to an electrode, an optical laminate that does not cause corrosion of the electrode may be provided.

Hereinafter, the present application will be described in detail through examples, but the scope of the present application is not limited by the following examples.

Evaluation items and evaluation methods

One. Peeling force ( gf / 25mm)

Each adhesive polarizing plate prepared in Examples and Comparative Examples was cut so that the horizontal length was 25 mm and the vertical length was 200 mm to prepare specimens, and was attached to the glass plate via the adhesive layer of the specimens. Peel strength was measured while peeling the adhesive polarizing plate at a 90 ° peel angle and a 300 mm / min peel rate at a time point after the specimen was attached.

2. High temperature durability (high temperature reliability)

Each adhesive polarizing plate prepared in Examples and Comparative Examples was cut so that the length of the horizontal was about 140 mm and the length of the vertical was about 90 mm, thereby preparing a specimen, which was 5 kg / cm ² on a glass substrate. Attached under pressure. The attachment was performed in a clean room to prevent bubbles or foreign matter from occurring. Subsequently, the prepared sample was kept in an autoclave for 15 minutes at 50 ° C and 5 kg / cm ² .

After maintaining the sample at a temperature of about 100 ° C. for about 500 hours, durability was evaluated according to the following criteria.

<Evaluation criteria>

O: No bubbles and peeling were observed

Δ: bubbles are generated, and peeling is partially observed.

X: Bubbles and peeling were severely observed

3. Throwing power (Missing) evaluation

The keying force is a physical quantity that reflects the adhesive force between the pressure-sensitive adhesive layer and the substrate. Each pressure-sensitive adhesive layer prepared in Examples and Comparative Examples was laminated to a release film on a polarizing plate, aged for 7 days at constant temperature and humidity conditions (23 ° C 50% relative humidity), and aging for the sample. Was evaluated. Specifically, after removing the release film of the pressure-sensitive adhesive layer from the sample, the Americal Tapel pressure-sensitive adhesive tape having a width of about 50 mm is attached to the pressure-sensitive adhesive layer of the sample, and when the pressure-sensitive adhesive layer is separated from the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer is attached to the polarizing plate. It was evaluated by visually checking how much remains. The weaker the keying force, the more the pressure-sensitive adhesive layer is separated from the polarizing plate, which is an adherend during evaluation, and transferred to the adhesive tape, and accordingly, the more vacancy of the pressure-sensitive adhesive in the pressure-sensitive adhesive layer located on the polarizing plate. As described above, when there are many vacancy, it can be considered that the throwing power is weak.

<Evaluation criteria>

◎: No empty space was observed in the adhesive layer located on the polarizing plate

○: The area of the empty space observed in the pressure-sensitive adhesive layer located on the polarizing plate is 10% or less of the total pressure-sensitive adhesive layer area

△: The area of the empty space observed in the pressure-sensitive adhesive layer located on the polarizing plate is within 10 to 30% of the total pressure-sensitive adhesive layer area

X: The area of the empty space observed in the pressure-sensitive adhesive layer located on the polarizing plate is 30% or more of the total pressure-sensitive adhesive layer area

4. ITO corrosion

Each pressure-sensitive adhesive composition prepared in Examples and Comparative Examples was laminated on a 40 μm-thick TAC (Triacetyl cellulose) film, and the pressure-sensitive adhesive layer aged for 7 days at constant temperature and humidity conditions (23 ° C. 50% relative humidity). Was prepared. A commercially available ITO (Indium Tin Oxide) film is cut to a width of about 50 mm and a length of about 30 mm to prepare a specimen, and on each end in the transverse direction, a width of about 10 mm is applied. Silver paste was applied. Subsequently, the pressure-sensitive adhesive layer was cut to have a length of about 40 mm and a length of about 30 mm to prepare a specimen on the silver paste with an interval of about 5 mm at an end. After the prepared ITO film was preserved for 250 hours at a high temperature and high humidity condition (85 ° C 85% relative humidity), the rate of change of resistance compared to the initial input was evaluated with a line resistance meter (Hioki 3244-60 card hitester).

<Evaluation criteria>

◎: Resistance change rate is less than 40%

○: Resistance change rate within 40 to 100%

△: Resistance change rate is within the range of 100 to 180%

X: Resistance change rate is 180% or more

Example  One

(1) Preparation of adhesive polymer

N-butyl acrylate (n-BA), benzyl acrylate (BzA), methyl acrylate (MA) and acrylic acid (AA) were added to a 1 L reactor in which nitrogen gas was refluxed and a cooling device was installed to facilitate temperature control. 64: 15: 20: 1 was added in a weight ratio (n-BA: BzA: MA: AA) and 100 parts by weight of ethyl acetate (EAc) was added as a solvent. Subsequently, nitrogen gas was purged for 1 hour to remove oxygen, and 0.03 parts by weight of azobisisobutyronitrile (AIBN) diluted to 50% by weight in ethyl acetate as a reaction initiator was added, followed by reaction for 8 hours to obtain a weight average. A copolymer (A) having a molecular weight (Mw) of about 1.65 million was prepared.

(2) Preparation of adhesive composition

The copolymer (A) prepared in (1) compared to 100 parts by weight of solids, toluene diisocyanate (TDI) (trade name T-706BB) 0.8 parts by weight, a compound derived from hexamethylene isocyanate (HDI) represented by the following formula (A) Di-n-butyltin dilaurate (di-n-butyltin) diluted in ethyl acetate at a concentration of about 0.5% by weight after mixing 0.2 parts by weight and 0.005 parts by weight of an epoxy-based crosslinking agent (trade name: T-743L) dilaurate) -based catalyst (C-700, Hannong Chemical) is blended in about 0.001 part by weight based on 100 parts by weight of the copolymer (A) solid content, and additionally 1.5 parts by weight of a conductive additive (FC4400A diluted to 70%) and a crosslinking retarder As acetyl acetone, 100 parts by weight of the solid content of the copolymer (A) is blended to about 1 part by weight, diluted to an appropriate concentration, and the uniformly mixed coating solution is coated on a release paper and dried to have a thickness of 22 μm. Manufacture uniform adhesive layer It was.

[Formula A]

(2) Preparation of polarizing plate

A polyvinyl alcohol (PVA) film having a thickness of about 30 μm (Japan Synthetic Corporation, M2004) was immersed in a 30 ° C. dyeing solution containing 0.05% by weight of iodine and 1.5% by weight of potassium iodide for 60 seconds. Was treated by dyeing. The dyed PVA film was then crosslinked by immersion in a crosslinking solution at 30 ° C. containing 0.5% by weight of boron and 3.0% by weight of potassium iodide for 60 seconds. Thereafter, the cross-linked PVA film was stretched at a stretch magnification of 5.5 times using an inter-roll stretching method. The stretched PVA film was washed by immersion in 30 ° C of ion-exchanged water for 20 seconds, and then immersed in a solution of 30 ° C containing 1.5% by weight of zinc nitrate and 4.0% by weight of potassium iodide for 10 seconds. Then, the PVA film was dried at a temperature of 80 ° C. for 200 seconds to prepare a polarizer. The potassium content in the prepared polarizer was about 0.47% by weight, and the zinc content was about 0.17% by weight. Subsequently, on one side of the polarizer, the moisture permeability (WVTR) measured for 24 hours at 37 ° C 88.5 ± 0.5% relative humidity according to the standard (ASTM F1249, ISO15506-3) with 7002 Water Vapor Permeation Analyzer (Systech Illinois) equipment is about A polarizing plate was prepared by adhering an acrylic film of about 15 g / m ² · day with an adhesive, and attaching a known polarizer protective film TAC (triacetyl cellulose) film with an adhesive on the other side.

(4) Optical Of the laminate (adhesive polarizing plate)  Produce

The prepared adhesive layer was adhered to the acrylic film surface of the polarizing plate to prepare an adhesive polarizing plate (optical laminate).

Comparative example  1 to 9

As in Table 2, a pressure-sensitive adhesive composition, a polarizing plate, and a pressure-sensitive polarizing plate were prepared in the same manner as in Example 1, except that the crosslinking agent was different in type and content. For reference, Table 1 compares the NCO content of the HDI-based crosslinking agent used in each Example and Comparative Example.

[Table 1]

[Table 2]

[Table 3]

Claims (15)

Acrylic polymers having polar functional groups (A);
Aromatic isocyanate (B); And
Pressure-sensitive adhesive composition comprising an isocyanate compound (C) represented by the formula (1):
[Formula 1]

However, in Formula 1, R is an alkyl group having 1 to 10 carbon atoms, A1, A2 and A3 are each independently an alkylene group or an alkylidene group, m is an integer between 2 and 5, and n is 2 to 10 Is an integer between. The polymer (A) is an alkyl (meth) acrylate having an alkyl group having 4 or more carbon atoms, an alkyl (meth) acrylate having an alkyl group having 3 or less carbon atoms, an aromatic group-containing monomer, and a polar functional group-containing monomer. Adhesive composition comprising a. The pressure-sensitive adhesive composition according to claim 1, comprising 5 to 60 parts by weight of the isocyanate compound (C) represented by Formula 1 based on 100 parts by weight of the aromatic isocyanate (B). According to claim 1, wherein the polymer (A), based on 100 parts by weight of the aromatic isocyanate (B) and the isocyanate compound (C) represented by the formula (1) within a range of 0.001 parts by weight to 10 parts by weight of the pressure-sensitive adhesive composition. The adhesive composition according to claim 1, further comprising an epoxy-based crosslinking agent, an aziridine-based crosslinking agent, or a metal chelate-based crosslinking agent. The pressure-sensitive adhesive composition according to claim 2, comprising 15 to 45 parts by weight of an alkyl (meth) acrylate having an alkyl group having 3 or less carbon atoms, based on 100 parts by weight of an alkyl (meth) acrylate having an alkyl group having 4 or more carbon atoms. . The optical laminate according to claim 2, wherein the aromatic group-containing monomer is represented by the following Chemical Formula 2:
[Formula 2]

In Formula 2, R1 represents hydrogen or alkyl, A represents alkylene, n represents an integer in the range of 0 to 3, Q represents a single bond, -O-, -S- or alkylene, P represents Aromatic ring. The pressure-sensitive adhesive composition of claim 2, wherein the aromatic group-containing monomer is included in an amount of 10 to 40 parts by weight of the aromatic group-containing monomer, based on 100 parts by weight of the alkyl (meth) acrylate having an alkyl group having 4 or more carbon atoms. The pressure-sensitive adhesive composition according to claim 2, wherein the monomer having a polar functional group is a hydroxyalkyl (meth) acrylate or a carboxyl group-containing monomer having a hydroxyalkyl group having 3 to 6 carbon atoms. The pressure-sensitive adhesive composition of claim 2, wherein the monomer having the polar functional group is in the range of 0.5 to 5 parts by weight based on 100 parts by weight of the alkyl (meth) acrylate having an alkyl group having 4 or more carbon atoms. An optical element including an optical film having a moisture permeability of 100 g / m ² · day or less measured after storage for 24 hours at 37 ° C. and 88.5 ± 0.5% relative humidity; And
An optical laminate having a pressure-sensitive adhesive layer formed on one surface of the optical element and comprising a cured product of the pressure-sensitive adhesive composition according to claim 1. The optical laminate according to claim 11, wherein the optical film having a moisture permeability of 100 g / m ² · day or less is an acrylic film. The optical laminate according to claim 11, wherein the optical element is a polarizing plate. 12. The method of claim 11, The polarizing plate, Polarizer; And an optical film formed on one surface of the polarizer and having the moisture permeability. The optical laminate according to claim 11; And a display panel attached to the optical laminate via the pressure-sensitive adhesive layer of the laminate.